Experiments on Film Boiling Heat Transfer around a Vertical Finite-Length Aluminum Cylinder with Convex Hemispherical Bottom

摘要

The film boiling heat transfer around a vertical finite-length aluminum cylinder with con-vex hemispherical bottom was investigated experimentally for quiescent water at atmospherericpressure. The experiments have been carried out by a transient method, i.e., quenching method.The diameter of test cylinder is 32mm and the total length is 48mm with 32mm length of verticallateral part. The test cylinder was heated to about 560°C in an electric furnace and then cooledin saturated and subcooled water with the immersion depth of about 100mm. The degree of liquidsubcooling was varied from 0 to 30K. The film boiling heat transfer increased in terms of heat fluxby 230% with an increase 30K in liquid subcooling at the wall superheating of 300K. The wallsuperheating and heat flux at the lower limit of film boiling increased with an increase in liquidsubcooling. Further, the experimental results for an aluminum cylinder were compared with thosefor a silver cylinder.